The present invention relates generally to audio playback devices, and more particularly to controlling the output volume.
Media assets, such as audio tracks, video tracks, or images (e.g., photos) can be stored, displayed, and/or played on a portable media device (“PMD”) or on a host computer executing a media management application (“MMA”). Often, a portable media device acquires its media assets from a host computer executing an MMA, and the user may use the MMA to organize the collection of media assets. One example of a PMD may be the iPod® portable media device, currently available from Apple Inc. of Cupertino, Calif. One example of an MMA may be iTunes® media management application, produced by Apple Inc. Some PMDs provide the user a display to aid in interacting with the content on the PMD.
One reason for the popularity of PMDs and MMAs is the ability to store and manage very large collections of audio and video tracks, to arrange them into playlists, and to arrange to have tracks from a variety of sources within the collection played back in any desired order (or randomly if desired). In recognition of the fact that music CDs (and downloadable tracks) are mastered differently, with large discrepancies in volume between songs on different albums, iTunes® and the iPod™ have been provided with what is referred to as the “Sound Check” feature, which allows the user to standardize the volume of all the songs in the collection. This feature can be enabled or disabled at will.